Brake lining



Dec. 21, 1937. A. RosNER 2,102,855

BRAKE LINING Original Filed Dec. 21, 192B 2 Sheets-'Sheet lVIII/11111111 l Villar/1111,11' l IN V EN TOR. ,lido/ph @o5/7er* IW QATTORNEY A. ROSN ER BRAKE LINING Dec. 21, 1937.

original Filed Dec. 21, 192s 2 sheeis-sneei 2 INVENTOR.

Ado/ph Poner BY CC A TTORN E Y Patented Dec. 21, 1937 UNITED STATESPATENT OFFICE BRAKE LINING Adolph Rosner, Rockton, Ill., assigner toBendix Brake Company, SouthBend, Ind., a corporation of IllinoisOriginal yapplication December 21,1928, Serial No. 327,730. Divided andthis application January 22, 1934, Serial N0. 707,654

4v Claims.

This invention relates to friction materials such as brake lining, andhasr for its object the provision of a lining, preferably of the woventype.

which will be fiat on the shoe without curling at the edges and whichwill not stretch or "creep laterally.

Ordinary brake linings are made flat, and when a strip is 'curved to beplaced on a shoe a set of unbalanced strains is set up which causes thelining to curl away from the shoe at its edges giving a channel-shapedeffect which leaves upturned edges which engage the brake drum be- -forethe central portion of the lining. The edges of course wear downsomewhat in service, but in so doing the edges of the lining becomefrayed and ragged, and moreover the lining never overcomes its tendencyto curl.

According to one phase ofthe present invention, the liningis formed sothat, when a .strip of it is straightened out, it is transversely con--cave. The upper and lower -faces of the lining are preferably onparallel arcs, and the concave side is toward the brake shoe. When astrip of this lining is bent to be placed on a shoe,- it

ilattens out transversely, so that it lies at against the shoe with notendency to curl.

I prefer to make the transverse curvature slightly greater vthan wouldcause the lining to become exactly straight transversely when so bentlongitudinally so that there is still a slight concavity facing towardthe shoe; then when the rivets or other fastenings draw the liningtightly against the shoe the side edges are drawn down under tension andclosely.

In order to make sure that there will not be any ragged or frayed edgesas the lining wears, I prefer to bevel the side edges of the lining. g.

hug the shoe all the more Another difficulty encountered with /ordinarybrake lining is their tendency to stretch out or creep transverselywhile in service, so that they roverhang:` vthe Yshoe and.` give aragged and@ un- (Cl. 18S-250) ness into the transverse elements orfiller 'of the weave, so that ordinary braking pressure in use readilycauses the lining to ow or creep transversely.

In order to avoid this, I weave or otherwise form the lining thicker butnarrower than it is finally to be', and then roll or otherwise compressit to the correct thickness with its'edges unsupported and free to flowoutwardly to size, thus taking out all the stretch and in fact leavingthe transverse elements set under tension. Preferably the side of thelining ilows outwardly into a convergent space, thus forming theabove-described bevel.

The rolls or'other compressing devices also of course can be formed togive the lining the desired transverse curvature.

The above and other objects and advantages of the invention will beapparent from the following description when taken in connection withthe accompanying drawings, which are submitted for purposes ofillustration and are not intended to define the scope of the invention,reference being had for/that purpose to the subjoined claims.

In the drawings wherein similar reference characters refer to similarparts throughout-the several views-- Figure 1 is a diagrammaticperspective view of a brake shoe, with the lining partly in place on theshoe and partly extending straight outwardly at atangent to the shoe;

Figure 2 is a section through the shoe and lining, on the line 2-2 ofFigure 1;

Figure 3 isa section, on line 3-3 of Figure 1,

through the shoe and a straight portion of the lining;

Figures 4 and 5 are sections corresponding respectively to Figures 2 and3 but showing ordinary brake lining;

Figure 6 is a diagrammatic view showing the compressing of the lining tosize between-a pair Figure 7 is a diagrammatic section showing thearrangement of the longitudinal and transverse elements of the weave ofa piece of lining before it is compressed;

Figure 8 show s what would happen if it were compressed laterally only;

Figure 9 shows what happens when it is compressed both laterally and forthickness; and

Figure 10 shows what happens when the same lining is compressed,according to my method, with its side edges unsupported.

in the drawings, the character I2 indicates a well-known form of rigidbrake shoe having a now the lining is bent into an arc longitudinally tobe placed on a shoe or the like, as shown in Figure 4, there is atendency to compress the lower portion that is the portion below theneu'- tral central plane n-n lengthwise through the lining, and tostretch the upper portion that is the portion above the plane n n. Atthe oppositesides of the lining these opposite forces are not balanced,and cause the lining to curl transversely, away from the shoe. Asexplained above this soon results in frayed and ragged edges, as it isimpossible to place the rivets in such a manner as to pull the liningentirely flat against the shoe.

According to my invention, the lining I6, when straight (Figure 3) hasupper and lower transversely-curved parallel faces I8 and 20, so thatthe lining as a whole is concave, with the vconcave side facing towardthe shoe. When this lining is bent on an arc against the shoe, as inFigure 2, it straightens out transversely, or substantially so,

` and lies flat against the shoe.

I prefer, however, to make the curvature slightly greater than thatnecessary to cause the ldesired flattening out, so that there is still avery shallow concavity facing toward the shoe, so that when the liningis drawn tightly against the face I4 by the rivets or their equivalentthe outer edges of the lining will be tensioned against the shoe andwill hug tightly against the shoe to form a very close joint. A

In order to make certain that there will not be any fraying at theedges, I also prefer to bevel the upper edges `(i. e. the edges awayfrom the shoe) as shown at 22.

As shown in Figure 6, the lining may be formed as described above asbeing compressed between devices such as novel rolls 24 and 26. I preferalso to take 'advantage'of this step in the manu-- facture ofthe liningto secure the above-described place at any time before or aftercompressing the linin'g, according to the method of manu-` facture). Inthis diagram the longitudinal ele--v ments are shown in section at 28,these usually being a copper-wire and asbestos yarn, and the transverseelements or filler (of the same material). `are shown in elevation at 30weaving in and out among the elements 28 in the usual manner.`

Ordinarily this material has a width A which is greater than the nalwidth desired, and a thickness B which is greater than the nal thicknessdesired, and the next st ep would be to compress it both transverselyand for thickness If the compression transversely took place first, andthe compression for thickness as a second step, Figures 8 and 9 showwhat would happen. First (Figure 8) the transverse l compression wouldelongate the vertical loops of the elements 30, leaving clearances 32about the elements 28. Next (Figure 9) these loops would be flattenedout at 3d, giving broad transverse loops loosely embracing the elements28. Substantially the same /thing happens in the usual step of combiningthe transverse compression with the compression for thickness. It willbe seen that this gives a nal material which has a diminished tensilestrength transversely, and which readily flows or creeps transversely inuse. v

As shown in Figure l0, I prefer to compress to the" desired flnalthickness B-Y" without confining or restraining the material laterally,but

. in fact facilitating the lateral flow of the material during thecompression. To this end, I take a piece of material which is thickerbut narrower than the desired final, product, and while compressing itfrom the thickness "B to B-Y", it is allowed to stretch or flowlaterally from a width A to a greater width A-l-Z. It will at once beapparent 4that this sets the transverse elements 30g under tension, sothat there is if vanything a negative tendency to stretch, and since theresulting pre-stretched fabric will never in been claimed in mycopending application Serial No. 327,730, filed December 21, 1928, ofwhich this application isa division. A K

It is expressly understood that the scope of my invention is to belimited by nothing appearing herein except the appended claims.

I claim: -Y

1. A friction materialA for attachment to a brake shoe or the like andwhich is formed in a long strip having, when the strip is straight,parallel transversely-curved upper and lower faces presenting aconcavity on the side which is to engage the shoe, which concavity tendsto ilatten out as the strip is bent Ainto the arc of the shoe, and whichstrip is of woven material with transv.verse elements set under tensionso that there vset under tension so that there is substantially notendency for the material to stretch transversely under pressure.

3. A friction material for attachment to a brake shoe or the like whichis in the form of an elongated strip stretched transversely during *to adesired width A-X and a desired thikv manufacture so that'it tends tovcontract rather ness B-Y.

than expand transversely during use.

4. A transversely prestretched brake lining."

ADoLpH RosNER.

